بررسی اثر سیکل دمایی قبل از بارگذاری سیکلی بر روی عمر خستگی صفحات دارای تداخل و تخمین عددی عمر خستگی

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی مکانیک، دانشگاه تبریز،تبریز، ایران

چکیده

فرآیند تداخل یک تکنیک مؤثر برای بهبود عمر خستگی اتصالات می‌باشد و بصورت گسترده در صنایع مختلف به ویژه هوا-فضا و صنایع خودروسازی برای افزایش عمر خستگی اتصالات مورد استفاده قرار می‌گیرد. بررسی مطالعات انجام گرفته در زمینه فرایند تداخل نشان می‌دهد که تاکنون اثر تغییرات دما به عنوان عاملی تأثیرگذار بر روی عمر خستگی، مورد مطالعه قرار نگرفته است. بر این اساس، در مقاله حاضر تأثیر اعمال بارگذاری کوتاه مدت سیکل دمایی قبل از بارگذاری سیکلی، بر روی عمر خستگی صفحات سوراخ‌دار که تحت عملیات تداخل قرار گرفته‌اند بصورت تجربی و عددی بررسی شده است. اثر تغییرات دما با در نظر گرفتن دو سیکل دمایی 60 و 120 درجه سانتی‌گراد، مورد بررسی قرار گرفته است. تست‌های خستگی بر روی آلیاژ آلومینیم 7075-T6 انجام شده و نمودار تنش-عمر برای نمونه‌ها بدست آمده است. برای بدست آوردن تنش‌ها و کرنش‌های ناشی از فرایند تداخل و اعمال سیکل دمایی و همچنین تنش‌ها و کرنش‌های ناشی از اعمال بار‌های تناوبی مختلف، از یک مدل سه بعدی المان محدود در نرم‌افزار انسیس استفاده شده است. در نهایت، نتایج تحلیل تنش به منظور تخمین عمر خستگی نمونه‌ها بکار گرفته شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of thermal cycle effect prior to cyclic loading on fatigue life of interference fitted specimens and fatigue life prediction

نویسندگان [English]

  • Hadi Taghizadeh
  • Navid Chakherlou Tajbakhsh
The Faculty of Mechanical Engineering, University of Tabriz
چکیده [English]

Interference fit process, as a popular method, is used in aerospace and automotive industries to improve fatigue life of the joints. Investigating studies on interference fit process demonstrates that the effect of temperature variations has not been studied as an effective factor on fatigue life. In the present study, the effect of short time exposure to thermal cycle before cyclic loading on fatigue life of interference fitted fastener holes have been evaluated by experimental and numerical methods. So, to investigate the effect of temperature variations two different temperatures (i.e. 60°C and 120°C), aside from room temperature, were selected to accomplish this study. Fatigue tests were carried out on the specimens of Al-alloy 7075-T6 to obtain S-N curves. In relation to fatigue tests, three dimensional finite element analyses were used to explain the experimental results. The interference fit process, and subsequent thermal cycles and remote cyclic loading were simulated using Ansys package. The results obtained from the finite element analyses of the interference fit were employed to predict the fatigue life.

کلیدواژه‌ها [English]

  • Fatigue life
  • Interference fit
  • Thermal cycle
  • Finite element
  • Multiaxial fatigue
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